You Must Go to Several Websites to Find the Cheapest Airfare Instead of Assuming That Any One is the Budget Champion

Recently, the New York Times carried an article by Seth Kugel in which he reached the unsurprising conclusion that ethnic travel agents specializing in one destination can get better airfares for you than are accessed from the internet's airfare search engines. Going to Zagreb, Croatia? Going to Shenzhen, China? Visit (or phone) a live Croatian-American travel agent for the former or a live Chinese-American travel agent for the latter, and they will get you a fare costing considerably less than you'd obtain from Expedia, Travelocity, or Orbitz. Since these are human beings sending hundreds of people to a single destination, they have obviously negotiated better airfares with the airlines going to their exotic hub cities.
 
To that conclusion, I'd like to add a personal discovery. Going to a standard, mass-volume destination -- like London or Paris or Denver or Cancun -- no one service, neither a search engine website nor a live travel agent, will always get you the best fare. I've been amazed in recent tests of the Internet to discover how fickle they all are. On one test to a particular city, Orbitz will have the best fare. Or another test to a different city, Dohop.com will have the best fare, on still another, Kayak will have the best fare. For reasons hard to explain, there's no science or logical explanation of why particular websites are the occasional price leaders to one city but not to another.
 
And as I've recently discovered, the airfare aggregators like Momondo or Dohop.com or Skyscanner.com will usually have better airfares than the giant search engines like Expedia or Travelocity -- but not always. Sometimes, and occasionally, in a crazy alternation of customary roles, such giants as Expedia or Orbitz or Travelocity will actually be the price leaders!
 
So what does this all mean, in terms of your own tactics in obtaining a good airfare to your next vacation destination? It means that you can't quickly find such a fare; you must, instead, spend an hour or so going to all the sources -- to places like CheapTickets.com and CheapOAir.com and Kayak and Momondo and Orbitz -- to fully take advantage of the crazy structure of airfares. Different services have different airfares, and any claim that they all discover the same opportunities is totally mistaken. The lazy would-be traveler pays the most; the person willing to spend an hour or so at the task of searching for a bargain -- will often find one.
 
Am I right in reaching that conclusion? Has your own experience been different? Is there any one airfare search engine that always (or usually) leads the field? I'd be grateful for your comments.